A reference document on Permissible Limits for solvents and buffers during in vitro antimalarial screening

Abstract

Antimalarial drug discovery expands on targeted and phenotype-based screening of potential inhibitory molecules to ascertain overall efficacy, phenotypic characteristics and toxicity, prior to exploring pharmacological optimizations. Candidate inhibitors may have varying chemical properties, thereby requiring specific reconstitution conditions to ensure solubility, stability or bioavailability. Hence, a variety of solvents, buffers, detergents and stabilizers become part of antimalarial efficacy assays, all of which, above certain threshold could interfere with parasite viability, invasion or red blood cell properties leading to misinterpretation of the results. Despite their routine use across malaria research laboratories, there is no documentation on non-toxic range for common constituents including DMSO, glycerol, ethanol and methanol. We herein constructed a compatibility reference guide for 14 such chemicals and estimated their Permissible Limit against P. falciparum asexual stages at which viability and replication of parasites are not compromised. We also demonstrate that at the estimated Permissible Limit, red blood cells remain healthy and viable for infection by merozoites. Taken together, this dataset provides a valuable reference tool for the acceptable concentration range for common chemicals during in vitro antimalarial tests.

Antimalarial Activity of Aqueous Extracts of Nasturtium (Tropaeolum majus L.) and Benzyl Isothiocyanate

“…The stock solutions were made in compliance with the maximum solvent limits that can be used in antimalarial assays [52]. Keeping this in mind, a stock solution of BITC (Sigma-Aldrich®) with 112.5 μg/ml (754 μM) containing 90% dimethyl sulfoxide (DMSO; Sigma-Aldrich®) was diluted in sterile PBS (VWR TM ) to achieve a DMSO percentage in the assays ≤ 0.4%.…”

Diamond Magnetic Microscopy of Malarial Hemozoin Nanocrystals

“…However, the movement of red blood cells would need to be constrained such that crystals remain close to the diamond surface. This may be accomplished by promotion of cell adhesion [48] or sedimentation [49], confinement of cells within microstructures [36,50], and/or increase of the viscosity of the surrounding medium [51–53]. If the platform is simplified and miniaturized, it may also find application as a label-free malaria diagnostic tool with sensitivity rivaling the current staining or microscopy standard [18].…”

Development of catalytic asymmetric P(III)-C bond formations in ferrocenyl, heterobicyclic & exocyclic olefins

“…Samples fixed in 0. and late schizont stage parasites (~46-48 hpi) were stained with 5M of CellROX Green (Invitrogen -ThermoFisher scientific) for 30 minutes and Hoechst 33342 for last 5 minutes of incubation in MCM at 37C in dark. In addition, parasites were treated with either selected ferrocenyl compounds at 10 M or DMSO (0.03%) 38 as negative control. As positive control, hydrogen peroxide was used under similar experimental conditions.…”

“…The catalytic mechanism of Pd(II)-catalyzed P-H additions to activated alkenes (see Figure 1) has been studied and was described to characteristically include phosphine coordination, phosphide addition and protonation steps. 38 Origins of the regio-and stereoselectivities of AHP utilizing aminopalladacycle (S)-2 have been comprehensively discussed 31a, 39 and summarized as follows:…”